658 POLYPI. 



L^raniilis, that it dries entire on the axis, and retains its colours, whicli are often very briglit and beautiful ; but it 

 is soUiliIi- in acids. The Polypi of several species have been examined, and found to have eiy^ht toothea ttnta- 

 cula, and a stnmach and other viscera, like those of Corollium. 



Amon<; them, M. Lamouroux disting-uishes Plexaures, which have flie covering; membrane thick, with the cells 

 not prominent, and it eftervesces but sIiL,"htly witli acids ; Ennu-en, whicli ha\'e the same back, but the cells of 

 thr polypi prominent ; Miirisen, which have the coverini^of moderate ttiickness, with projoctinfj mamniillEe co\'ered 

 ^v^th roiii2:h and imbi-icated scales ; jm&Prlmnoa, in which the mamillK become ImbricatL-d by the one hanging- 

 partially over the other, 



LiTI-JOrHVTA, — 



The second trdie, liavc a fixed internal axis of stony consistency. Tlie leading gem ra are, /.v/.v, 

 Modrepora, and MiUipora ; ))iit they admit of subdivision. 



hlSy have the axis branched, and no cells or cavities on its surface ; and the interna! tunic of f^elatinons matter 

 is mixed with calcareous particles, as in Gorg^onia. 



CoraU'uia [his noh'di.s of LinucTeus], is the Coral of commerce, so much admired for its fine red colour, and the 

 h;g;h polish i.*i which it is susceptible, and so often made into trinkets. There are very profitable fishing^s (or 

 divings) for it in different parts of the Mediterranean. The co;'(;ring- is uf a n.'ddish colour, and contains cal- 

 careous matter. The polypi have eight toothed arms, or tentacnhi. Mdihi, has the stony axis internipted by 

 nodes full of a substance of the consistency of cork. /.v/.s-, iiropcrly so called, has the liorny part knotty; and 

 the bark thick, soft, and easily removed after death. Moju-ia, has the bark much thinner, but also stronger. 



Madrepora (the Madrepores), — 

 Have their stony substance sometimes branched, and sometimes in rounded masses, or in leaves; Init 

 it is always furnished witli lainin;c, cuiieenf rated toward pointi in the form of slars, or teiminating in 

 lines more or less serpentine. During life the stony part is enveloped in a hornv bark, ■which is soft 

 and gelatinous, and roughened by rosettes of teutacula. which are the Polypi, or rather the Actinire, for 

 they have more than one row of tentacula. Tlic lamina? of the polypi have some slight rer>eml>laiice 

 to tho^e on the stony ease; and the covering an<J itolypi contract a litrlc upon being tmielird. 



The varieties of their general form, and the figures which are produced by the combinations of their lamina?, 

 have been made the foundation of numerous subdivisions ; but sevei-al of these run into others, so that they are 

 not absolutely specific, and it will be impossible to fix them definitely until the relations between their forms 

 and the polypi are known. 



When there is only a single star, circular or elongated, -with many lainiiin\ they are the /'^'Hr;/,M)f L;nnarck ; 

 and their pnlype resembles a single Actinea, with nnnu'rons tentaeula ; and tlie opcinng of the mouth correspuuds 

 exactly with the point toward which the lamina' i^on\'erge. 



There are found among fossils stony pub pidnms consisting of a single siar. wlmh appears never to Jia\e 

 adhered to others. These are the TinhiiKihi and CjicloVtUnis of Lamarck, and the Turhii/o/op.fjs, Lamouroux. 



When the Madrepore is branched, and Ihe stars are confined to the extremities <it eai h luanrh, i( is tlie Cnn;o- 

 j-lnillla of Lamonrnux. Tin- luanelies are sti-iated, and each star auswei's to a mnutli suirmmded by uiany 

 tentacula. 



Oc(ifi)ia, ha\-e the small lateral bi-anches very short, which gives them the appearance of having stars along the 

 brancUfs, as well ;is nn Ihe extrt-ndties. Madrcporn, or Madrepores properly so called, have the whole surface 

 roughened by littli' stars. 7^M^'V/y;lr^/^7, have little stars with pores in the intervals ; k\m\ Serialojim-a^ ha\e their 

 stars in lines. A-sfn-a, lia\'e a broad and generally convex surface, hollowed by crowded stars, eaeh li;a ing a 

 polype with numei-ous Icntaenhi in a single row, in the centre nt wbicb is the mouth. E.rplanaria, are broad, 

 with the stars on one sidr. I'<<rit<:s, lias the sioiiy substance branched. Mmiidrinay have the surface formed into 

 little hills and valleys. In each valley there are mouths ; but the teutacula, instead of forming stars or rosettes 

 aninnd them, are ranged along the sides of the valley. In some, however, the mouths are merely festooned. If 

 the hills which separate the valleys are raised into crests furrowed on both sides, they are called Pai'o^i/fi ; and 

 mouths, usually without tentacula, are found in the valleys, the crests probably acting as substitutes for the latter. 

 There are also others, which have these hills conical or star-shaiied, and the princijial rlistinctJon of thent is 

 having the pnlypi nn thf innjieting parts nr in lln' hollnws. Aij'uii nui, air composed uf lamina', having valleys 

 only on the run.' side, and the sides of the valleys fiin-ou cd. It is inailiabli' that we should consider as near!/ 

 allied to the Madrepores, certain polypidoms cnniposed of r'ylindcrs. the sections uf wlneh fbiin stars. These are 

 Sarcimda, and when they have a solid axis, they are perbafis nearly allied to Tubipora, in the llrst family of the 

 order. 



iMlLLirORA, — 



M'liich coni]iose the third genus, have tlw stnuy portion miudi divcrsitied in shape, and tlic surface 

 scooped only into small holes or pores, and smiietimrs there are no apparent iicrforatiims. I>/.\/ic//o- 

 pora, have strongly marked pnrcs on t\Mi sid(\s of tiie brauidies. Mill'ipora piMpcr, are sidid and 

 variously hranelied. Sometimes thi- pores are not discernible, and they are X'dl/jiorr.w Exchora. have 

 flattened and leaf-like expansions. Relojmra, are EschorEe pierced like a net-uork. Adi-ona, are 

 Esehorac on articulated stems, entire, or pierced like a net-work. 



